The present invention pertains to processes and apparatus for forming a lap seam, and more particularly to processes and apparatus for making prefastened disposable absorbent garments including lap seams.
Garments such as disposable absorbent garments have numerous applications including diapers, training pants, feminine care products, and adult incontinence products. The typical disposable absorbent garment is formed as a composite structure including an absorbent assembly disposed between a liquid permeable bodyside liner and a liquid impermeable outer cover. These components can be combined with other materials and features such as elastic materials and containment structures to form a product that is specifically suited to its intended purposes.
What is lacking and needed in the art are processes and apparatus for forming lap seams such as for the manufacture of prefastened disposable absorbent garments.
In response to the above-referenced unfulfilled need in the art, new processes and apparatus for forming lap seams and making prefastened disposable absorbent articles have been discovered.
In one aspect, the invention concerns an apparatus for positioning a pair of panels in overlapping orientation. The apparatus comprises a transport system defining a machine center line, an interior folding mechanism adapted to position a first panel in an interior position, and an exterior folding mechanism adapted to position a second panel in an exterior position relative to the interior position. The interior folding mechanism comprises a mandrel transversely spaced from the machine center line and defining a curved peripheral surface, and an interior forming shoulder in proximity to the mandrel and defining an interior surface disposed toward the mandrel and an opposite exterior surface. The curved peripheral surface and the interior surface define an inner passage therebetween. A fluid pressure device is operatively associated with the inner passage and adapted to establish an air flow through the inner passage.
In another aspect, the invention concerns an apparatus for positioning first and second panels in overlapping orientation, comprising: a transport system defining a machine center line; an interior panel folding mechanism adapted to position a first panel in an interior position; and an exterior panel folding mechanism adapted to position a second panel in an exterior position relative to the interior position. The interior panel folding mechanism comprises a mandrel transversely spaced from the machine center line and defining a curved peripheral surface. The interior panel folding mechanism also comprises an interior forming shoulder defining an interior surface disposed toward the mandrel, an opposite exterior surface, a distal edge, and a head portion adjacent the distal edge and in contact with the mandrel. The curved peripheral surface and the interior surface define an inner passage therebetween, and a fluid pressure device is operatively associated with the inner passage and adapted to establish an air flow through the inner passage and against the interior surface.
In another aspect, the invention concerns an apparatus for positioning first and second panels in overlapping orientation, comprising a transport system defining a machine center line, and an interior panel folding mechanism adapted to position a first panel in an interior position. The interior panel folding mechanism comprises: a mandrel transversely spaced from the machine center line and defining a body having a curved peripheral surface, an internal mandrel chamber within the body, and an aperture through the body and in communication with the internal mandrel chamber; an interior forming shoulder in proximity to the mandrel and defining an interior surface disposed toward the mandrel and an opposite exterior surface, the curved peripheral surface and the interior surface defining an inner passage therebetween; and a fluid pressure device operatively associated with the inner passage and adapted to establish an air flow through the inner passage and into the internal mandrel chamber; and an exterior panel folding mechanism adapted to position a second panel in an exterior position relative to the interior position.
In another aspect, the invention concerns a method for forming a lap seam. The method comprises transporting first and second panels in a machine direction, where the first and second panels are discontinuous in the machine direction. The first panel is fluidly directed onto a curved peripheral surface of a mandrel as the first panel is transported in the machine direction. A second panel is positioned transversely outward from the first panel, with the first panel disposed between the curved peripheral surface and the second panel. The first and second panels are either permanently or refastenably bonded together.
In another aspect, the invention concerns a method of forming a lap seam, comprising: transporting first and second panels in a machine direction with a mandrel comprising a curved peripheral surface disposed between the panels, the first panel disposed between the curved peripheral surface and an interior surface of an interior forming shoulder, the curved peripheral surface and the interior surface defining an inner passage therebetween; establishing an air flow through the inner passage such that the first panel is fluidly directed toward the curved peripheral surface; positioning the second panel transversely outward from the first panel, with the first panel disposed between the mandrel and the second panel; and bonding the first and second panels together.
In yet another aspect, the invention concerns a method for progressively folding first and second discrete panels to form a lap seam. First and second panels are transported in a machine direction. A mandrel is introduced in proximity to the first panel. The mandrel defines a body having a curved peripheral surface. An air flow is established and directed toward the first panel at multiple machine direction positions, such that the air flow directs the first panel toward the curved peripheral surface. The method also includes modifying the direction of the air flow at downstream machine direction positions so that the air flow increasingly folds the first panel over the curved peripheral surface as the first panel is transported in the machine direction. The second panel is positioned transversely outward from the first panel, and the first and second panels are bonded together.
In still another aspect, the invention concerns a method for seaming a pant with first and second pairs of side panels, comprising: transporting a folded pant in a machine direction, the folded pant having opposite first and second waist regions in facing relation, including first side panels of the first waist region in facing relation with second side panels of the second waist region; positioning the first side panels adjacent mandrels having curved peripheral surfaces; creating air flows adjacent the first side panels to direct the first side panels toward the curved exterior surfaces; modifying the direction of the air flows at downstream machine direction positions; and bonding the respective first and second side panels together.
In another aspect, the invention concerns a method for making a pant. The method comprises providing a pant chassis defining a first waist region, a second waist region, a crotch region which extends between and interconnects the waist regions, first side panels disposed in the first waist region and second side panels disposed in the second waist region. The pant chassis is folded about a fold line extending in a lateral direction through the crotch region, thereby positioning the waist regions and respective first and second side panels in a facing relation. The folded pant chassis is transported in a machine direction with mandrels disposed between each of the facing first and second side panels, such that each first side panel is disposed between a curved peripheral surface of a mandrel and an interior surface of an interior forming shoulder. Each curved peripheral surface and each interior surface define an inner passage therebetween. An air flow is established through each inner passage such that each first side panel is fluidly directed toward a curved peripheral surface. Each second side panel is positioned transversely outward from its respective first side panel, with the first side panel disposed between the mandrel and the second side panel. The overlapping first and second side panels are bonded together.
The garments can include permanently bonded side seams or refastenable side seams. Non-refastenable seams can be formed by ultrasonic bonds, adhesive bonds, thermal bonds, sewing, or the like. Fastening components to form refastenable seams can comprise separate elements bonded to another component of the pant. Alternatively, the fastening components can comprise a portion of another element of the pant, such as the bodyside liner, the outer cover, separate side panels if employed, integral side panels if employed, a belt-type component extending transversely across the chassis if employed, or the like. Thus, unless otherwise specified, the term xe2x80x9cfastening componentxe2x80x9d includes separate components which function as fasteners and regions of materials such as side panels, liners, outer covers or the like which function as fasteners. Moreover, a single material can define multiple fastening components to the extent that different regions of the material function as separate fasteners. The fastening components can be located on the side panels, between the side panels such as on the absorbent chassis, or a combination of the two. The fastening components can have any desired shape, such as square, rectangular, round, curved, oval, irregularly shaped, or the like. Each fastening component can comprise a single fastening element or multiple fastening elements.
The fastening components can comprise any refastenable fasteners suitable for absorbent articles, such as adhesive fasteners, cohesive fasteners, mechanical fasteners, or the like. In particular embodiments the fastening components comprise mechanical fastening elements for improved performance. Suitable mechanical fastening elements can be provided by interlocking geometric shaped materials, such as hooks, loops, bulbs, mushrooms, arrowheads, balls on stems, male and female mating components, buckles, snaps, or the like. In particular embodiments, the fastening components and mating fastening components comprise hook-and-loop fastening elements. One skilled in the art will recognize that the shape, density and polymer composition of the hooks and loops may be selected to obtain the desired level of securement between the fastening components and the mating fastening components. A more aggressive hook material may comprise a material with a greater average hook height, a greater percentage of directionally-aligned hooks, or a more aggressive hook shape.
A refastenable fastening system allows for easy inspection of the interior of the pant-like product. If necessary, the fastening system also allows the pant to be removed quickly and easily. This is particularly beneficial when the pant contains messy excrement. For training pants, the caregiver can completely remove the pant-like product and replace it with a new one without having to remove the child""s shoes and clothing. Refastenable or non-refastenable fastening systems may be used with a wide variety of absorbent and non-absorbent products, including training pants, swim pants, diaper pants, incontinence garments, feminine care products, health care garments, apparel for institutional, industrial and consumer use, or other garments using mechanical or adhesive fasteners.
Absorbent articles are adapted to be worn adjacent to the body of a wearer to absorb and contain various exudates discharged from the body. The absorbent articles are desirably prefastened to provide a pant-like product for the user. The product can then be pulled on like a conventional training pant, and subsequently checked or removed with the ease of a diaper-like product. Moreover, the product may be applied like a diaper rather than like a pant. Supplemental releasable fastening means such as frangible point bonds may be employed to maintain the absorbent article in a pant configuration until the user intentionally disengages the fasteners.
Particular training pants suitable for use with the present invention are disclosed in U.S. patent application Ser. No. 09/444,083, filed on Nov. 22, 1999 (corresponding to PCT application WO 00/37009 published Jun. 29, 2000) by A. Fletcher et al. and titled xe2x80x9cAbsorbent Articles With Refastenable Side Seams;xe2x80x9d which is incorporated herein by reference. This reference describes various materials and methods for constructing training pants. Training pants can also be constructed using the methods and apparatus disclosed in U.S. Pat. No. 4,940,464 issued Jul. 10, 1990 to Van Gompel et al.; and U.S. Pat. No. 5,766,389 issued Jun. 16, 1998 to Brandon et al.; which are also incorporated herein by reference.
Within the context of this specification, each term or phrase below will include the following meaning or meanings.
xe2x80x9cBondedxe2x80x9d refers to the joining, adhering, connecting, attaching, or the like, of two elements. Two elements will be considered to be bonded together when they are bonded directly to one another or indirectly to one another, such as when each is directly bonded to intermediate elements. Lap seams as described herein can be formed with panels that are either permanently or refastenably bonded together.
xe2x80x9cComprisingxe2x80x9d is inclusive or open-ended and does not exclude additional, unrecited elements or method steps.
xe2x80x9cConnectedxe2x80x9d refers to the joining, adhering, bonding, attaching, or the like, of two elements. Two elements will be considered to be connected together when they are connected directly to one another or indirectly to one another, such as when each is directly connected to intermediate elements.
xe2x80x9cDisposablexe2x80x9d refers to articles which are designed to be discarded after a limited use rather than being laundered or otherwise restored for reuse.
xe2x80x9cDisposed,xe2x80x9d xe2x80x9cdisposed on,xe2x80x9d and variations thereof are intended to mean that one element can be integral with another element, or that one element can be a separate structure bonded to or placed with or placed near another element.
xe2x80x9cElastic,xe2x80x9d xe2x80x9celasticizedxe2x80x9d and xe2x80x9celasticityxe2x80x9d mean that property of a material or composite by virtue of which it tends to recover its original size and shape after removal of a force causing a deformation.
xe2x80x9cElastomericxe2x80x9d refers to a material or composite which can be elongated by at least 25 percent of its relaxed length and which will recover, upon release of the applied force, at least 10 percent of its elongation. It is generally preferred that the elastomeric material or composite be capable of being elongated by at least 100 percent, more preferably by at least 300 percent, of its relaxed length and recover, upon release of an applied force, at least 50 percent of its elongation.
xe2x80x9cFabricsxe2x80x9d is used to refer to all of the woven, knitted and nonwoven fibrous webs.
xe2x80x9cFlexiblexe2x80x9d refers to materials which are compliant and which will readily conform to the general shape and contours of the wearer""s body.
xe2x80x9cForcexe2x80x9d includes a physical influence exerted by one body on another which produces acceleration of bodies that are free to move and deformation of bodies that are not free to move. Force is expressed in grams per unit area.
xe2x80x9cGraphicxe2x80x9d refers to any design, pattern, or the like that is visible on an absorbent article.
xe2x80x9cHydrophilicxe2x80x9d describes fibers or the surfaces of fibers which are wetted by the aqueous liquids in contact with the fibers. The degree of wetting of the materials can, in turn, be described in terms of the contact angles and the surface tensions of the liquids and materials involved. Equipment and techniques suitable for measuring the wettability of particular fiber materials or blends of fiber materials can be provided by a Cahn SFA-222 Surface Force Analyzer System, or a substantially equivalent system. When measured with this system, fibers having contact angles less than 90xc2x0 are designated xe2x80x9cwettablexe2x80x9d or hydrophilic, while fibers having contact angles greater than 90xc2x0 are designated xe2x80x9cnonwettablexe2x80x9d or hydrophobic.
xe2x80x9cIntegralxe2x80x9d is used to refer to various portions of a single unitary element rather than separate structures bonded to or placed with or placed near one another.
xe2x80x9cInwardxe2x80x9d and xe2x80x9coutwardxe2x80x9d refer to positions relative to the center of an absorbent article, and particularly transversely and/or longitudinally closer to or away from the longitudinal and transverse center of the absorbent article.
xe2x80x9cLayerxe2x80x9d when used in the singular can have the dual meaning of a single element or a plurality of elements.
xe2x80x9cLiquid impermeablexe2x80x9d, when used in describing a layer or multi-layer laminate, means that a liquid, such as urine, will not pass through the layer or laminate, under ordinary use conditions, in a direction generally perpendicular to the plane of the layer or laminate at the point of liquid contact. Liquid, or urine, may spread or be transported parallel to the plane of the liquid impermeable layer or laminate, but this is not considered to be within the meaning of xe2x80x9cliquid impermeablexe2x80x9d when used herein.
xe2x80x9cLongitudinalxe2x80x9d and xe2x80x9ctransversexe2x80x9d have their customary meaning. The longitudinal axis lies in the plane of the article and is generally parallel to a vertical plane that bisects a standing wearer into left and right body halves when the article is worn. The transverse axis lies in the plane of the article generally perpendicular to the longitudinal axis. The article as illustrated is longer in the longitudinal direction than in the transverse direction.
xe2x80x9cMemberxe2x80x9d when used in the singular can have the dual meaning of a single element or a plurality of elements.
xe2x80x9cNonwovenxe2x80x9d and xe2x80x9cnonwoven webxe2x80x9d refer to materials and webs of material which are formed without the aid of a textile weaving or knitting process.
xe2x80x9cOperatively joined,xe2x80x9d with reference to the attachment of an elastic member to another element, means that the elastic member when attached to or connected to the element, or treated with heat or chemicals, by stretching, or the like, gives the element elastic properties; and with reference to the attachment of a non-elastic member to another element, means that the member and element can be attached in any suitable manner that permits or allows them to perform the intended or described function of the joinder. The joining, attaching, connecting or the like can be either directly, such as joining either member directly to an element, or can be indirectly by means of another member disposed between the first member and the first element.
xe2x80x9cOuter cover graphicxe2x80x9d refers to a graphic that is directly visible upon inspection of the exterior surface of a garment, and for a refastenable garment is in reference to inspection of the exterior surface of the garment when the fastening system is engaged as it would be during use.
xe2x80x9cPermanently bondedxe2x80x9d refers to the joining, adhering, connecting, attaching, or the like, of two elements of an absorbent garment such that the elements tend to be and remain bonded during normal use conditions of the absorbent garment.
xe2x80x9cRefastenablexe2x80x9d refers to the property of two elements being capable of releasable attachment, separation, and subsequent releasable reattachment without substantial permanent deformation or rupture.
xe2x80x9cReleasably attached,xe2x80x9d xe2x80x9creleasably engagedxe2x80x9d and variations thereof refer to two elements being connected or connectable such that the elements tend to remain connected absent a separation force applied to one or both of the elements, and the elements being capable of separation without substantial permanent deformation or rupture. The required separation force is typically beyond that encountered while wearing the absorbent garment.
xe2x80x9cRigidxe2x80x9d describes an element or structure that assumes a generally fixed position during use, where functionality does not depend significantly on movement and/or bending.
xe2x80x9cRupturexe2x80x9d means the breaking or tearing apart of a material; in tensile testing, the term refers to the total separation of a material into two parts either all at once or in stages, or the development of a hole in some materials.
xe2x80x9cStretch bondedxe2x80x9d refers to an elastic member being bonded to another member while the elastic member is extended at least about 25 percent of its relaxed length.
Desirably, the term xe2x80x9cstretch bondedxe2x80x9d refers to the situation wherein the elastic member is extended at least about 100 percent, and more desirably at least about 300 percent, of its relaxed length when it is bonded to the other member.
xe2x80x9cStretch bonded laminatexe2x80x9d refers to a composite material having at least two layers in which one layer is a gatherable layer and the other layer is an elastic layer. The layers are joined together when the elastic layer is in an extended condition so that upon relaxing the layers, the gatherable layer is gathered.
xe2x80x9cSurfacexe2x80x9d includes any layer, film, woven, nonwoven, laminate, composite, or the like, whether pervious or impervious to air, gas, and/or liquids.
xe2x80x9cTensionxe2x80x9d includes a uniaxial force tending to cause the extension of a body or the balancing force within that body resisting the extension.
xe2x80x9cThermoplasticxe2x80x9d describes a material that softens when exposed to heat and which substantially returns to a nonsoftened condition when cooled to room temperature.
These terms may be defined with additional language in the remaining portions of the specification.